linux-kernel - Re: [PATCH V3 3/7] backlight: qcom-wled: Add new properties for PMI8998

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Message-ID: <20180620190502.GA20160@rob-hp-laptop>
Date:   Wed, 20 Jun 2018 13:05:02 -0600
From:   Rob Herring <robh@...nel.org>
To:     Kiran Gunda <kgunda@...eaurora.org>
Cc:     bjorn.andersson@...aro.org, jingoohan1@...il.com,
        lee.jones@...aro.org, b.zolnierkie@...sung.com,
        dri-devel@...ts.freedesktop.org,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jacek Anaszewski <jacek.anaszewski@...il.com>,
        Pavel Machek <pavel@....cz>,
        Mark Rutland <mark.rutland@....com>,
        linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH V3 3/7] backlight: qcom-wled: Add new properties for
 PMI8998

On Tue, Jun 19, 2018 at 04:43:38PM +0530, Kiran Gunda wrote:
> Update the bindings with the new properties used for
> PMI8998.
> 
> Signed-off-by: Kiran Gunda <kgunda@...eaurora.org>
> ---
>  .../bindings/leds/backlight/qcom-wled.txt          | 84 ++++++++++++++++++++--
>  1 file changed, 77 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/leds/backlight/qcom-wled.txt b/Documentation/devicetree/bindings/leds/backlight/qcom-wled.txt
> index 14f28f2..503ce87 100644
> --- a/Documentation/devicetree/bindings/leds/backlight/qcom-wled.txt
> +++ b/Documentation/devicetree/bindings/leds/backlight/qcom-wled.txt
> @@ -48,11 +48,15 @@ platforms. The PMIC is connected to the host processor via SPMI bus.
>  - qcom,current-limit
>  	Usage:        optional
>  	Value type:   <u32>
> -	Definition:   mA; per-string current limit
> -		      value: For pm8941: from 0 to 25 with 5 mA step
> -			     Default 20 mA.
> -			     For pmi8998: from 0 to 30 with 5 mA step
> -			     Default 25 mA.
> +	Definition:   mA; per-string current limit; value from 0 to 25 with
> +		      1 mA step. Default 20 mA.
> +		      This property is supported only for pm8941.
> +
> +- qcom,current-limit-microamp
> +	Usage:        optional
> +	Value type:   <u32>
> +	Definition:   uA; per-string current limit; value from 0 to 30000 with
> +		      2500 uA step. Default 25000 uA.

This doesn't really seem worth adding just to add '-microamp'.


>  - qcom,current-boost-limit
>  	Usage:        optional
> @@ -79,12 +83,61 @@ platforms. The PMIC is connected to the host processor via SPMI bus.
>  		      27, 29, 32, 35. default: 29V
>  		      This property is supported only for PM8941.
>  
> +- qcom,ovp-millivolt

Is this the same as qcom,ovp? If so, same comment.

> +	Usage:        optional
> +	Value type:   <u32>
> +	Definition:   mV; Over-voltage protection limit;
> +		      For pmi8998: one of 18100, 19600, 29600, 31100
> +		      Default: 29600 mV
> +		      If this property is not specified for PM8941, it
> +		      falls back to "qcom,ovp" property.
> +
>  - qcom,num-strings
>  	Usage:        optional
>  	Value type:   <u32>
>  	Definition:   #; number of led strings attached;
> -		      value from 1 to 3. default: 2
> -		      This property is supported only for PM8941.
> +		      value: For PM8941 from 1 to 3. default: 2
> +			     For PMI8998 from 1 to 4. default: 4
> +
> +- interrupts
> +	Usage:        optional
> +	Value type:   <prop encoded array>
> +	Definition:   Interrupts associated with WLED. This should be
> +		      "short" and "ovp" interrupts. Interrupts can be
> +		      specified as per the encoding listed under
> +		      Documentation/devicetree/bindings/spmi/
> +		      qcom,spmi-pmic-arb.txt.
> +
> +- interrupt-names
> +	Usage:        optional
> +	Value type:   <string>
> +	Definition:   Interrupt names associated with the interrupts.
> +		      Must be "short" and "ovp". The short circuit detection
> +		      is not supported for PM8941.
> +
> +- qcom,enabled-strings
> +	Usage:        optional
> +	Value tyoe:   <u32 array>
> +	Definition:   Array of the WLED strings numbered from 0 to 3. Each
> +		      string of leds are operated individually. Specify the
> +		      list of strings used by the device. Any combination of
> +		      led strings can be used.
> +		      for pm8941: Default values are [00 01].
> +		      for pmi8998: Default values are [00 01 02 03].

u32 or u8 because dts syntax for 8-bit array is [].

> +
> +- qcom,external-pfet
> +	Usage:        optional
> +	Value type:   <bool>
> +	Definition:   Specify if external PFET control for short circuit
> +		      protection is used. This property is supported only
> +		      for PMI8998.
> +
> +- qcom,auto-string-detection
> +	Usage:        optional
> +	Value type:   <bool>
> +	Definition:   Enables auto-detection of the WLED string configuration.
> +		      This feature is not supported for PM8941.
> +
>  
>  Example:
>  
> @@ -99,4 +152,21 @@ pm8941-wled@...0 {
>  	qcom,switching-freq = <1600>;
>  	qcom,ovp = <29>;
>  	qcom,num-strings = <2>;
> +	qcom,enabled-strings = <0x00 0x01>;
> +};
> +
> +pmi8998-wled@...0 {

led-controller {

And needs a unit-address.

> +	compatible = "qcom,pmi8998-wled";
> +	reg = <0xd800 0xd900>;
> +	label = "backlight";
> +
> +	interrupts = <3 0xd8 2 IRQ_TYPE_EDGE_RISING>,
> +		     <3 0xd8 1 IRQ_TYPE_EDGE_RISING>;
> +	interrupt-names = "short", "ovp";
> +	qcom,current-limit-microamp = <25000>;
> +	qcom,current-boost-limit = <805>;
> +	qcom,switching-freq = <1600>;
> +	qcom,ovp-millivolt = <29600>;
> +	qcom,num-strings = <4>;
> +	qcom,enabled-strings = <0x00 0x01 0x02 0x03>;
>  };
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>  a Linux Foundation Collaborative Project
>